Two-level defense (American Football Strategy)

In American football, a two-level defense is a defensive formation with only two layers of defense instead of the customary three layers.

In a usual three-level defense, there are three layers: the forcing unit (consisting mainly of linemen but possibly also including shooting linebackers and defensive backs), the underneath coverage (usually consisting of linebackers but possibly including other players, especially in the case of a zone blitz), and the contain unit (mostly defensive backs). A two-level defense does away with the contain unit in favor of increased pressure on the offense. Two-level defenses will often use one deep safety (as deep as 28 yards at the snap) to enforce an end line on the offense, but the Bear 4-6 is a two level defense with contain handled solely by the single coverage skills of the cornerbacks. The "Bear" can also function as a three-level defense, and indeed concealment of the defensive structure is a key to making this defense work.

The two-level was invented to combat the run and shoot offense in the 1980s, but has stayed in use due to its adaptability in combating all types of offenses. The defense of spread formations remains a strong suit of this model.

SPORTS

American Football

Game play in American football consists of a series of downs, individual plays of short duration, outside of which the ball is dead or not in play. These can be plays from scrimmage – passes, runs, punts, or field goal attempts (from either a place kick or a drop kick) – or free kicks such as kickoffs and fair catch kicks. Substitutions can be made between downs, which allows for a great deal of specialization as coaches choose the players best suited for each particular situation. During a play, each team should have no more than 11 players on the field, and each of them has specific tasks assigned for that specific play.